I am an idiot...3D Probe with Probe Basic

So I am trying to probe a PCB, which is 1.5mm thick, but the probe drops down too far. The EXTRA PROBE DEPTH should be able to accept a negative number to compensate for this.

What do I change to set the depth the probe drops below the Z height. I could lay something of a known thickness on top of the PCB but that defeats the purpose.

This really needs to be implemented in the UI, maybe I am not seeing something???

It uses the probe tip diameter for the base depth which is standard, if you need less you would typically use a stylus ball suited to the requirement. But I think that idea to allow negative number in Calc is worthwhile to investigate.

I'm away from dev, but in the interim, you can use the straight probe functions which don't require z to move at all during probing, or like you mentioned, use a shim.

Mine is already quite puny at 0.078". If I knew where to change the code to let it accept a negative number, I would make the change myself. Is the input text box set to only allow for positive numbers, because it removes the leading negative. If that were the case it may be an easy fix.

Sorry was trying to edit this post and hit delete on accident.   

Depending how you installed probe basic you may or may not have access to the probe_basic.yml file.  If you do,  you can do the following:

Change the min value shown in the file below to:
min_value: -100



 

I was able to test the change recommended above and confirmed it does now accept negative entries in the extra probe depth user entry.  the change has been pushed to the latest version, for 2.8.4 you will need to manually update it in a dev installation.

 

I will try to make a video this week and post the link, I will go through all I know about probing which isn't much. Maybe it will be a help to someone.

Thank you for your help, much appreciated.